This invention is directed to triazole nucleosides and to their use as antiparasitic agent particularly the triazole nucleosides 1-(5'-0-sulfamoyl-.beta.-D-ribofuranosyl)[1,2,4]triazole-3-carboxamide, 1-(5'-0-sulfamoyl-.beta.-D-ribofuranosyl)[1,2,4]triazole-3-thiocarboxamide and 1-(5'-O-sulfamoyl-.beta.-D-ribofuranosyl)[1,2,4]triazole-3-carbonitrile.
Parasitic diseases are a scourge of essentially all higher organisms. The protozoa and other pathogens which cause these diseases are wide spread and cause much pain, suffering and economic loss world wide. Control of certain of these pathogens is difficult because of the life cycle of the parasite is divided between a vector and a further host or hosts. Invertebrates can often serve as the vector as, for instance, in the various forms of trypanosomiasis and leishmaniasis. In other of there parasitic disease, e.g. trichomoniasis, the parasite can be spread directly within a species often times between the sexes of that species and in further parasitic diseases such as giardiasis spread is from one species to a different species.
Certain nucleosides have been shown to exhibit antiparasitic properties. The first chemical synthesis of a sulfamoyl nucleoside, 5'-O-sulfamoyl adenosine, was reported by D. A. Shuman, M. J. Robins and R. K. Robins, J. Am. Chem. Soc., 1969, 91, 3434 (1969). Unfortunately while 5'-sulfamoyl adenosine was active in-vitro against certain parasites, it was also found to be extremely toxic.
1-(.beta.-D-Ribofuranosyl)[1,2,4]triazole-3-carboxamide (Ribavirin), is a relatively non-toxic broad spectrum antiviral agent. It has also been shown to be a substrate for adenosine kinase in certain human cell lines in-vitro. It however does not have antiparasitic activity.